Leavening is the process of making breadstuffs lighter and fluffier. This is accomplished by putting a gas, most often CO2, sometimes air, into the dough before baking. This can be accomplished by mechanical means (the beaten egg whites for Angel Food Cake for example) biological (yeast producing CO2) or by a chemical reaction producing a gas as a reaction from heat, a reaction between an acid substance and an alkaline substance or sometimes a combination of both. . The subject for this time is the chemical reaction type and how this affects us as 19th Century cooks, I will cover the different types in the order they evolved.

Hartshorn

Before I get to the acid based chemical reactions to leaven breadstuffs, there is one that was fairly common at one time, but is seldom used today except for historic recipes that specifically call for it, this is a product often called hartshorn or bakers ammonia (Ammonium bicarbonate). This chemical in times was made from dry distilling hart’s horns, hart being an Old English name for male deer (the horn actually being antlers) this, when heated releases ammonia which leavens the product, today it is made by other processes. Harts horn’s exact origins have been hard to track down exactly because of different sources giving wildly varying dates. I can find reliable reference to it as far back the late 17th Century and may actually date further back, and considering that it is used in a lot of German baking I’d even hazard a guess that it was developed there.

Hartshorn has a couple disadvantages as well as advantages; the big disadvantage is it gives the product a slight ammonia taste, so it is limited to items like ginger bread, anise cookies including the German. Springerle a popular cookie for Christmas in Germany, as well as ones spiced with coriander, the sweetness and the strong flavor of the spices help cover the ammonia tastes. The other big disadvantage is unless it is kept in a tightly sealed container it will degrade quickly. The advantages of it is goods baked with it are generally lighter and crisper than the other forms of leavening and also stay fresh longer. Hartshorn can be found in some specialty shops as well as obtained off the internet.

Before I get to the other chemical leavenings a quick review of a little basic chemistry, acids when mixed with an alkaline substance will produce gas, acids when mixed with a carbonate will evolve CO2 as a gas, this is the basis of the grade school science experiment where baking soda (Sodium bicarbonate) is mixed with vinegar which contains about 5% Acetic acid, the mixture then foams up of course and in what is called a gas evolution reaction releases a quantity of CO2 (Carbon dioxide) gas. This is the basis of the chemical leavening agents used to make most quick breads such as biscuits, cookies and most cakes baking powders and any recipe involving an acid substance such as sour milk and baking soda use this process.

PearlashA carbonate is used in most cases, to react with an acid substance to form CO2, the first to come into common use dates back in time, but was not commercially produced till the late 18th century, this being Potassium carbonate, know in the past by the common name of pearl ash. Good hard wood ashes contain a lot of Potassium carbonate; the extraction of this from the wood ashes involves leaching water through the ashes and collecting the liquid, this of course forms lye which is Potassium hydroxide, straining the water then boiling the water the water, and heating enough to drive the locked in water out forms Potassium carbonate, which is what formally was known as Pearl Ash. Clean ash itself can also be used and is sometimes referred to as Pearl Ash, but it leaves other residue in the goods, but it was used at times when one needed leavening and had no other source. The acid used in this reaction was most often either lactic acid in soured milk, butter milk or the citric acid in molasses. This formed CO2 which leavened the bread, this method had problems, the most common was the Potassium Carbonate could react with the fats in the dough and give it a soapy taste, and we all probably know that lye and fats are used to make soap, and the water in the dough dissolve the Potassium carbonate and form a weak lye solution which can react with the fats before it is neutralized by the acid. Like the Hartshorn it is best used with heavily flavored products such as gingerbread, this helps cover the off taste that is often produced.

Baking SodaAbout this same time another product was being developed in Europe, this being Sodium bicarbonate, a product that had been used since ancient times in its impure form, the mineral Natron, one of the vital parts of Egyptian mummification, and glass making for centuries.

Purified Sodium bicarbonate worked like Pearl Ash in baking and reacts with an acid substance to form CO2 to cause a bread product to rise; it had the advantage of not creating the off taste that Pearl Ash did. Small amounts were imported but it did not become and important part of American cooking till the 1840’s when manufacture of this chemical began in this country. This chemical is referred to by many names, perhaps the most popular in 19th century America was Salertus a corruption of the Latin term “sal æratus” which means aerated salt. It is also referred to as “Bicarbonate of Soda” as well as the one in most use today, “Baking Soda.” This quickly became the alkaline chemical of choice for raising bread stuff, partly because it did not have the disadvantages of the pearl ash as far as off taste and worked well with any acid substance such as sour milk, sourdough starter or molasses.

The advent of baking powders did not end the using of salertus as a leavening agent; this was still a cheaper way to quick leaven breadstuffs, even today it is a cheaper way to leaven if you have the acid liquid source such as sour dough starter or sour milk, sour milk of course being a common commodity in the days before good refrigeration and sourdough being a staple among chuck wagon cooks and miners.

Most will know that in equal volumes, our Sodium bicarbonate will raise four times the bread product as baking powder and baking powder costs an average of 4-6 times as much as baking soda. Now today the low cost of these will not make a difference to the average person, but in the past depending on ones situation, it could, a good example for fun would be a settler out in Custer County Nebraska, proving up on a claim, cash money was scarce but most had a cow or two and milk was easy to obtain and even easier to let go sour. So some cash strapped people continued to use this method despite the availability of baking powders as well as staying with the methods of cooking they were familiar with.

Another advantage of baking soda over baking powder many of us might not think of today in our era of modern tight sealing plastic containers is that in the time most containers that baking powder and baking soda were sold in a tin can with a friction fitting lid, these were fairly water resistant but far from water tight, if baking powder gets wet the reaction will start and the baking powder will be ruined, with baking soda water may cause the product to cake, but it can be crushed, then dissolved in the liquid and it will still work, although the results might not be perfect.

Baking Powders

Single Acting Baking PowdersAs baking soda was becoming an available item to American consumers, another product was being developed by chemists in the 1840’s that would be a big revolution in baking; this was what was called at first “Baking Powders” although today we call it simply “Baking Powder.” This product is a powdered alkaline substance (in most cases Sodium bicarbonate) and an acidic powder and in the modern product a neutral substance to prevent caking, this in most cases is corn starch.

You may have noticed I used the plural baking powders as the name for this product at first, there is a valid reason for this, the first packaged baking powder was sold in two separate envelopes, one containing Sodium bicarbonate and the other containing twice the volume of the first and having “Cream of Tarter” (Potassium bitartrate) an acidic powder that is a by-product of wine making. This was an improved solution to raising bread products with out yeast (also a problematic process at the time before commercial processed yeast) but it still was not with out problems, the supply of cream of tarter coming mostly from France and Italy and relying on supply of the grape harvest in those areas. However despite the flaws, for many this was a product that made baking easier, especially those with a bit of extra spending money and a well stocked store near by.

A big change was about to take place in the middle 1850’s, a Harvard professor named Eben Norton Horsford replaced the cream of tarter in baking powder with “Calcium acid phosphate” a much cheaper acid powder and one not dependant on the grape harvest in Europe. Horsford began to manufacture his product as Horsford Bread Preparation in the separate envelopes like the earlier product was, but he quickly changed his formula and it was renamed Rumford Baking Powder and was manufactured at the Rumford Chemical Company a business he helped found.

His baking powder mixed both active ingredients and added a third, corn starch, another recent product development which served as to prevent the mix from caking as well as keeping the two chemicals from reacting prematurely by absorbing moisture in the air. This allowed a simpler way of quick leavening breads by just measuring the amount into the product. The ratio of the mix is 1 part Sodium bicarbonate, 1 part corn starch and 2 parts Calcium acid phosphate. This also made converting recipes from using and acid liquid such as sour milk easy; one just used sweet milk instead of the soured and used 4 times as much baking powder as one used baking soda. Other companies followed suit with slightly different formulas to Rumford to by-pass the patent, some using Potassium bicarbonate a similar alkaline chemical to Sodium bicarbonate.

All these types of early baking powders are what are called single-acting, this means as soon as they are moistened, the acid and the alkaline react producing CO2, but this reaction is limited of course, when the products reach a neutral state the CO2 quits forming, with a single-acting baking powder the cook needs to get the product mixed and in the oven in a timely manner, otherwise the CO2 will start to leak out of the dough and the product will end up being flatter than desired.

Double Acting Baking PowdersBy the late 1880’s another development was in the works, the so called double-acting baking powder, the first was developed by George Campbell Rew and William M. Wright, they marketed the product under the name Calumet Baking Powder.

This is a baking powder that has two different acid powders in the mix, one is quick acting, and is most often our Calcium acid phosphate of the past, although it may be listed by the newer name of Calcium dihydrogen phosphate, the other is one that reacts with the alkaline substance with the introduction of heat, this gives one a longer time till the product has to be baked, the partial release of CO2 does not stretch to dough/batter to the limit, and the heat from baking finishes the leavening, these types are more forgiving than the older single-acting type. These alkaline chemicals are most often either Sodium aluminum phosphate or Sodium acid pyrophosphate also known as Disodium pyrophosphate.

The type using Sodium aluminum phosphate have one big disadvantage and one possible one, the proven one is that depending on how sensitive ones taste is, the aluminum can often be tasted in the final product if it is something plain like a biscuit or corn bread, heavily sweetened/spice products will mask it just like the did with Hartshorn or Pearl Ash although the taste of the aluminum compounds is not as heavy. The other problem that has never been proven or disproved either, is the possible link between aluminum and dementia, I will not comment on this further, I leave that decision up to you, I avoid this type because I do not like and often notice the metallic taste in the product and buy non-aluminum baking powder so that leaves that worry behind.

The non-aluminum types most often use Sodium acid pyrophosphate also known as Disodium pyrophosphate as the second heat reaction alkaline substance, more and more are going to this, if the container does not say aluminum free on it just check the ingredients to see if it contains Sodium aluminum phosphate.

So as a historical cook what do we do with this information? Well for myself, since I do mostly outdoor cooking and mostly Civil War to the start of The Great War in Europe, I don’t plan on making any fancy ammonia cookies in camp and since both baking soda and baking powders are common items of my period, I will pass on the pearlash also. For those who’s demonstrations would be right for those items, I’m only going to offer this advice since I have never used them, if you want to make recipes that call for either, follow a period recipe as to instructions and if neither of these products can be found locally, our modern internet again is a good source for many scarce items.

As for the baking powder and baking soda, I will start with what most will probably use, the baking powder, as I explained, the modern double-acting type come into play in the very late 19th century, the all in one single-acting type comes into play right at the start of The Civil War, and the “baking powders” in separate envelopes comes in during the middle 1840’s.

If one wants to duplicate the early non-mixed baking powders, the process is really simple, you need two paper envelopes, one about twice as big as the other, in the small one, put Sodium bicarbonate and in the other one put twice as much Cream of Tarter. One can then use any recipe calling for modern baking powder, you just need to do a little simple math, first remembering that modern baking powder has ¼th the volume of it’s bulk as cornstarch an inert ingredient as far as our chemical reaction (remember it’s to prevent caking) and then the Sodium bicarbonate is 1/3rd of the active ingredients with 2/3rds being the acid part no matter what chemicals used. For measuring this type when using these type baking powders with recipes calling for modern baking powders it is simply measure 1/4th as much for the Sodium bicarbonate and ½ for the cream of tarter. When the dough is mixed, it needs baked as soon as possible, since this is a single acting type and will quickly neutralize and the CO2 production will stop and the gas will leak out of the dough, making it flatter than desired.

Next we come to single-acting baking powders, this is the type most commonly used from just before the Civil War till double-acting came out and single-acting never fully replaced it, Rumford still makes a single-acting type and there are some imported from France and Germany, to tell for sure, if it list only one acid powder, it is single-acting and if it lists two, then it’s double-acting. To be 100% historically correct, this is what should be used for historic demos. Like the separate baking powders, it needs mixed and the product cooked as soon as possible to keep the product from going flat.

That brings us to the newer, more common double-acting baking powder that came out in the 1890’s and how it fits into our scheme of historical demonstrations, well to be honest, I use it most of the time in my camp cooking, the reason is cost, I buy a 60 oz plastic can of it about once a year at a national big box store, I then repackage it for my cooking trips, and I pay about $5 for it, plus it is an aluminum free one like I prefer, although this is not a problem with the single-acting type. At almost all my demonstrations I am dealing with the general public, for most, the fact I am cooking outside in a dutch oven brings enough questions and to be honest, most of the general public, even the majority of those who cook from scratch do not know the difference or even the existence of the different types. In almost 20 years of doing demos I have been asked several times when baking powder was invented, but even that is so seldom it has maybe happened a dozen times, I find the general public is often so awed at the fact that someone can either cook outside or think from perhaps experience in Boy Scouts or similar encounters that you are limited to stews, cobblers and similar simple items, and if questioned I would freely admit to using the double acting and explain why.

Another reason to use the double acting baking powder is I have started doing some demonstrations for elementary aged school kids for Living History Days/Pioneer Days events; standard procedure for these is a group of demonstrators set up somewhere and the kids spending 20-25 minutes at each station, my main goal is to have something in a dutch oven baking at all times and I find simple biscuits is the easiest and making small biscuits I can give a sample to 200 or more kids in a 6 hour period. By using a double acting baking powder (or in many cases self-rising flour that has it in already) I can mix a 5 pound bag of flour up at a time, (this will fill a 16” oven as well as a 14” oven) I can then keep baking with minimal time to mix up another batch, if I get ahead I can switch to a smaller oven, to make sure I have something baking at all times.

I mentioned in my previous piece on wheat and flours, that “self-rising flour” (it already has the salt and baking powder in it) came on the market in the 1850’s and was a handy item for many, the baking powders added have followed the trend as the baking powders themselves have improved. Most use the aluminum based (or what I’ve bought) but it’s a price we have to pay for connivance. This was a common item sutlers sold Civil War soldiers and a common supply for the traveling person because of the connivance, for the historical cook it is still handy if one does not plan on making any yeast type bread and for me, it is something to talk with visitors about because it is not as commonly used or as well known as other places in the country such as down south where it is a staple in many kitchens.

When working with baking powders a good rule of thumb is most products will use about 1 tablespoon of baking powder per cup of flour, one can go down to about ¾ of a tablespoon for a product with a little less loft and if using a non-aluminum type, up to 1 ¼ or slightly more can be used to give extra loft, the 1 tablespoon rule should not be increased for an aluminum based baking powder, because it will increase the metallic taste often associated with these types.

Using baking soda aka Sodium bicarbonate aka Salertus in conjunction with an acid liquid in a recipe is not complicated, in fact with a little background information it is easy to convert recipes calling for baking powder to use cultured milk/butter milk or dough starter to create the chemical reaction. These products have been soured by the action of lactic bacteria converting the milk sugars (lactose) to lactic acid. True buttermilk is what it sounds like, it is the liquid left over after cream has been churned to make butter, true butter milk can either be sweet or sour, most people who make butter at home or at living history demonstrations use sweet cream, and sweet buttermilk will not react with the baking soda, most commercial made butter is done after the cream has been cultured (unless it says sweet cream butter) this makes it churn easier.. Another item not well known is the cultured buttermilk sold in stores is not in most cases true butter milk but skim milk that has been cultured, this is not a problem they are chemically very close, this is also available as a dehydrated form, how ever I have not been able to come up with a date as to when it was introduced, although it is not mentioned in The Grocer’s Encylopdia by Artemas Ward published in 1911, but it can be handy, mix your buttermilk ahead of time.

If one does not have cultured milk/buttermilk handy (or the powdered) fresh milk can be soured by placing 1 tablespoon of either vinegar or lemon juice in a scant cup of milk and stirring well, then letting it sit a short time. This will not be thick like true cultured milk/buttermilk, but it will work fine for all cooking.

With the baking powder the rule of thumb is to use 1 tablespoon of baking powder to 1 cup of flour, with the baking soda our rule of thumb changes, we base the amount we use on the liquid content our dough uses, the amount that works best (or at least is a base to start from) is ½ teaspoon of baking soda per cup of liquid.

Sour Milk/butter milk is pretty self explanatory, replace the liquid with the acidic product and use the ½ teaspoon of baking soda as a guide, if one wants the sour whang of the acidic product to stand out, then reduce the soda some, although this will also reduce loft of the final product (a bit of baking powder can be added to give more loft). When using sourdough starter to replace the liquid it gets a little bit more complicated because of the amount of solids from the flour used to feed it, a good rule of thumb is to uses about a 1/4th more starter than the amount of liquid the recipe being converted uses, of course the flour will need reduced accordingly, use the ratio of ½ teaspoon per level cup, rather than the extra amount added. This will take a little experimenting to get it right based on the thickness of your starter, but will put you close enough that most times it will work fine once you get the flour adjusted to the type of dough you are using.

When using baking powder in a recipe, some will call for both baking soda and baking powder. This may seem confusing at first, but it is often because some of the ingredients are slightly acid and the baking soda is used to reduce the acidity, but adds leavening at the same time. These recipes when they are studied do reduce the amount of baking powder compared to a similar recipe that does not use an acid in them. This is not a problem when following established recipes, but when going off on your own and developing recipes this needs to be taken into account.

I hope this helps you have a better understanding of chemical leavenings and how they work, plus how they are best used in our historical cooking.

Great stuff here. As a chemist, it almost sounds like school But, the connection between chemistry and cooking is a strong one and I won't hire a chemist who says they don't like to cook, or worse yet, can't cook.

For those who want to go the pearl ash route, as stated, a bit earlier than our timeframe, check out JAS Townsend and Sons. It sells primarily to the 18th century reenactor. They also have a great youtube channel that does 18th century cooking demos.

I am trying desperately to make gluten-free, egg-free, yeast-free, milk-free biscuits & bread.it is an experimental cooking nightmare.so far I use a rice-flour base, and have used baking soda and applesauce. now I think I must experiment with the soda-to-applesauce ratios, and find something like pork gelatin or guar gum to add "stickiness" so it can hold the gas.

Acclaimed By The Crowned Heads of EuropePurveyor of Patent Remedies, Snake Oil, Powder, Percussion Caps, Cleaning Supplies, Dry Goods, and Picture PostcardsOffering Unwanted Advice for All Occasions and Providing Useless Items to the GentrySince 1822[Available by Appointment for Lectures on Any Topic

Hi Prof,I have made some egg free items in the past for a friend with allergies. The most success I had was:1 tablespoon of ground golden flax seed3 tablespoons cold water.

mix and let stand for ~15 minutes. This is equivalent to 1 egg. has the right consistency and color. Made cookies with this and they were hard to distinguish from regular. (I am not blue and furry, but I know cookies, okay, a little furry, but not blue)

I have done gluten free cookies for a friend dealing with Crohn's,. It was the above egg substitute, sugar, real peanut butter and chocolate chips. Different but tasty. (too sweet in my opinion). Will see if I still have that recipe this weekend.

Acclaimed By The Crowned Heads of EuropePurveyor of Patent Remedies, Snake Oil, Powder, Percussion Caps, Cleaning Supplies, Dry Goods, and Picture PostcardsOffering Unwanted Advice for All Occasions and Providing Useless Items to the GentrySince 1822[Available by Appointment for Lectures on Any Topic

mix together, form into balls. back on a lightly greased cookie sheet for ~8-10 minutes at 350. These are really sweet, especially if you use commercial peanut butter. I ground my own at whole foods and it was a much less sweet version that was really pretty good. Friend with the issues likes them regardless as there is a limited amount of items they can eat.